Electric properties of semiconductor integrated circuits or the like are tested with a probe pin brought into contact with a large number of electrode pads thereof. Constituent materials of a probe pin are required to have various properties such as hardness for ensuring abrasion resistance for the test repeated several million times, oxidation resistance for preventing contamination of test objects caused by the generation of oxidation film, and low specific resistance for improving signal delay.
Copper alloy such as beryllium copper and phosphor bronze, tungsten and palladium alloy or the like have long been known as a material for a probe pin. However, these conventional materials do not have all required properties. For example, copper alloy and tungsten have sufficient mechanical properties but are relatively easily oxidized, and palladium alloy has good oxidation resistance but may be slightly inferior in hardness or the like.